High performance analog IC and sensor provider ams AG has introduced the AS3721, a power management IC (PMIC) with an innovative remote-feedback circuit designed to help reduce the thermal stress of applications processors in smartphones and tablets. When paired with ams’ new AS3729 point-of-load regulators, AS3721 provides a complete power management system that offers a fast response to load transients for reliable processor performance, high efficiency and flexible board layout.
The AS3721 PMIC enables a compact remote feedback path from the processor to the IC’s integrated DC-DC controllers. Thanks to a patent-pending design innovation, says the company, the feedback interface to the AS3721 only requires two wires—one control signal, one temperature signal— instead of the four or five wires typically required by other PMICs.
With fewer traces connecting the PMIC to the processor, the two devices can be placed far apart in the board layouts of space-constrained devices such as smartphones, tablets and notebooks. This dramatically reduces the size and intensity of the hotspot around the processor compared to conventional power architectures in which the processor and PMIC, both handling high currents simultaneously, must be located side-by-side.
The AS3721 PMIC features four DC-DC step-down regulators supplying 4A, 2A and 1.5A; three DC-DC step-down controllers rated for 5A, 10A and 20A; 12 digital LDOs; a real-time clock; a supervisor circuit; GPIOs; a general-purpose ADC; and a one-time programmable boot sequence. The device’s 8mm x 8mm BGA package features a pitch of just 0.5mm.
The complementary AS3729 contains NMOS and PMOS FETs for each of two phases, which can be controlled separately and can handle an output current of 2.5A. The PMIC can combine up to four devices in an eight-phase configuration that supplies a 20A maximum output.
